Squealing motor noise & choppy movement

Leeuw123

I just received and installed my new Duet 3 mini 5+ board with RepRap configured firmware. Everything works except that the motors make a loud and annoying squealing/screeching noise with current applied. When I turn off current to the motors, the noise goes away. The motors do move along their axes but with what I would consider to be less than ideal motion.

My config has the motors at a current of 800ma and I have tried with interpolation/no interpolation/stealthchop but nothing helps.

The motors themselves seem fine and work without noise with my old duet 2.

Any thoughts?

jay_s_uk

@Leeuw123 try adding D3 V40 to each M569 line

dc42

@Leeuw123 what VIN voltage are you using to power the Duet?

Leeuw123

@dc42 12v in. Basically, I took an ender 3 s1 set-up (gantry/motors/hotend) and am running it off my new duet 3 mini

Leeuw123

@jay_s_uk I will try that, thank you

Phaedrux

@Leeuw123 said in Squealing motor noise & choppy movement:

@dc42 12v in. Basically, I took an ender 3 s1 set-up (gantry/motors/hotend) and am running it off my new duet 3 mini

Aren't the creality printers running 24v supplies?

Leeuw123

@Phaedrux It can run either. I've had it set at 12v from the beginning.

Leeuw123

@jay_s_uk You are a beautiful human being! Worked like a charm. Motors sound perfect. Many, many thanks for taking the time to share your expertise.

droftarts

@Leeuw123 Just so you understand what has changed, and the effect of that, see M569

The M569 D parameter lets you choose the mode of operation between stealthChop (D3) and spreadCycle (D2). stealthChop is a quiet mode of operation for stepper motors at standstill and at low velocities, but will struggle at higher speeds. While stealthChop is a voltage mode PWM controlled chopper, spreadCycle is a cycle-by-cycle current control. It can react extremely fast to changes in motor velocity or motor load. spreadCycle will give better performance in medium to high velocity range for motors and applications which tend to resonance.

spreadCycle is the default mode of operation, because printers have been getting faster, and reaching the limitations of stealthChop, causing missed steps. RepRapFirmware also allows you to switch over from stealthChop to spreadCycle, using the V parameter. However, this changeover needs to happen at a relatively low speed, as there is a jolt when the changeover happens. The higher the changeover speed, the worse the jolt.

The V parameter defines at what speed this happens, except V isn't the actual speed, it is the interval in clock cycles between 1/256 microsteps below which the drivers will switch from stealthChop to to spreadCycle mode. Low V means the changeover happens at high speed, high V means it happens at low speed.

We suggest the use of one of the following configurations:

stealthChop changing over to spreadCycle a very low speed. Compared to running in spreadCycle always, this reduces standstill noise with some motors.
stealthChop changing over to spreadCycle at a little over your normal maximum printing speed. It will switch to spreadCycle for travel moves, except very short ones. This will only be viable if the jerk at switchover is tolerable.
Limit your travel speed so that you can keep the printer in stealthChop mode always.

Send M569 P... to see the speed this changeover happens, and tune V to a sensible speed for your setup. eg On my machine, if I send

M569 P0.0 S0 D3 V40
18/12/2024, 13:53:56 	M569 P0.0
Drive 0 runs in reverse, active low enable, timing fast, mode stealthChop, ccr 0x00053, toff 3, tblank 0, tpwmthrs 40 (117.2 mm/sec), pwmScaleSum 11, pwmScaleAuto 0, pwmOfsAuto 36, pwmGradAuto 14, pos 8

You can see the changeover speed is 117.2mm/s. I usually set the speed to be above 0mm/s, but below the jerk setting (M566, on my machine set to 5mm/s), so it's in spreadCycle for all movement, but stealthChop at standstill, like this:

M569 P0.0 S0 D3 V1000
18/12/2024, 14:24:59 	M569 P0.0
Drive 0 runs in reverse, active low enable, timing fast, mode stealthChop, ccr 0x00053, toff 3, tblank 0, tpwmthrs 1000 (4.7 mm/sec), pwmScaleSum 11, pwmScaleAuto 0, pwmOfsAuto 36, pwmGradAuto 14, pos 8

Tune the V parameter to get the right balance of noise reduction and performance for your machine.

Ian